Thrombosis is the formation of a thrombus, or blood clot, within the vascular system of a patient. A blood clot typically occurs when blood hardens from a liquid to a solid. When attached to vessel walls, blood clots, and other substances, such as plaque or fat, may reduce or block blood flow downstream from the clot. Chronic total occlusion (CTO) is a complete blockage within the vascular system or, more particularly, within an arterial vessel, that obstructs blood flow. This blocked blood flow may prevent critical blood flow and oxygen from reaching certain tissues and, thus, may result in damage to the tissues. Regardless of the particular location of the clot within the vascular system, a clot or, in particular, a CTO, if left untreated, may cause serious damage and, in some cases, may become life threatening.
A wide variety of invasive and non-invasive techniques are available for treating a CTO. For example, some percutaneous techniques include the use of pharmacological agents, also referred to as thrombolytic agents, to help dissolve the clots. Other percutaneous techniques may include the use of a wire guide and/or catheter to cross the occlusion and recanalize the vessel. However, crossing a CTO using a wire guide and/or catheter may be difficult and, oftentimes, impossible, due to the hardness of the clot or occlusion. During these recanalization procedures, it is common for the wire guide to be inadvertently advanced into the subintimal space of the vessel wall. Once the wire guide has entered the subintimal space, it is often difficult to redirect the wire guide back into the lumen of the vessel.
An exemplary lumen re-entry device is described in U.S. Patent Application Publication No. 2007/0219464 to Davis et al. Specifically, the Davis et al. reference teaches a steerable guidewire having a sharpened re-entry tip. The guidewire comprises a hypotube having a helical coil attached to and extending from a distal end of the hypotube. A retaining ribbon is connected to the distal end of the hypotube and is also connected to the sharpened re-entry tip. A deflection member is slidably disposed within the hypotube and has a distal end connected to the sharpened re-entry tip such that distal movement of the deflection member deflects the sharpened re-entry tip in one direction, while proximal movement of the deflection member deflects the sharpened re-entry tip in an opposite direction. While the lumen re-entry device of Davis et al. might offer successful deflection of the guidewire tip, the sharpened re-entry tip, which may be used for crossing an occlusion and/or re-entering a vessel lumen, may present risks of inadvertently puncturing or tearing the vessel wall during advancement and/or deflection.
The present disclosure is directed toward one or more of the problems set forth above.